Professional ballerinas, like highly driven young female athletes, face quadruple health threats — disordered eating, menstrual dysfunction, the bone-thinning disease osteoporosis, and early signs of cardiovascular disease.

It's known as the "female athlete tetrad," Dr. Anne Hoch of The Medical College of Wisconsin in Milwaukee told Reuters Health, and it starts with disordered eating.

Female athletes who don't eat enough to make up for the energy they expend during long workouts, may stop getting their period as a consequence, Hoch explained. These two components of the female athlete tetrad put them at higher risk for the other two — cardiovascular problems and bone density deficits — often seen in much older, postmenopausal women, she noted.

At the American College of Sports Medicine meeting in Seattle last week, Hoch reported on a study of 22 professional ballerinas from the Milwaukee Ballet Company. Their average age was 23 and their average weight was 114 pounds.

Eighty-six percent of the dancers had at least component of the female athlete tetrad and 14 percent had all four components.

Based on responses to a questionnaire, 36 percent of the dancers had disordered eating habits and 77 percent were in a calorie deficit. "They were not eating enough calories for the amount they were dancing," Hoch said.

More than half of the dancers (59 percent) were in a calcium deficit and 45 percent were in an iron deficit.

Twenty-seven percent of the dancers were currently not having menstrual periods. "It is not normal to stop having your period. If you haven't had a period in more than 3 months, that's abnormal and should be evaluated," Hoch said.

In addition, 23 percent of the dancers had low bone mineral density, which sets the stage for early osteoporosis, she added.

Perhaps most troubling, Hoch said, was the finding on ultrasound examinations that 64 percent of the dancers had premature blood vessel dysfunction, which is "the sentinel event that starts atherosclerosis (hardening of the arteries)," she warned.

"Being a female athlete you have to be very educated and knowledgeable about what you are at risk for," Hoch said. "You are at risk for eating issues, menstrual problems, low bone mineral density, and, now vascular problems, but this is all preventable if you are smart about the way you eat and exercise."

The bottom line, Hoch said: "Exercise as much as you want but be sure to fuel your body and eat enough calories."